/* ========================================================================
 * JCommon : a free general purpose class library for the Java(tm) platform
 * ========================================================================
 *
 * (C) Copyright 2000-2004, by Object Refinery Limited and Contributors.
 * 
 * Project Info:  http://www.jfree.org/jcommon/index.html
 *
 * This library is free software; you can redistribute it and/or modify it under the terms
 * of the GNU Lesser General Public License as published by the Free Software Foundation;
 * either version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
 * without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this
 * library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
 * Boston, MA 02111-1307, USA.
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 * 
 * -------------
 * RectangleEdge
 * -------------
 * (C) Copyright 2003, 2004, by Object Refinery Limited.
 *
 * Original Author:  David Gilbert (for Object Refinery Limited);
 * Contributor(s):   -;
 *
 * $Id: RectangleEdge.java,v 1.8 2004/04/26 19:15:44 taqua Exp $
 *
 * Changes:
 * --------
 * 14-Jul-2003 (DG);
 */

package net.droidsolutions.droidcharts.common;

import java.io.ObjectStreamException;
import java.io.Serializable;

import net.droidsolutions.droidcharts.awt.Rectangle2D;

/**
 * Used to indicate the edge of a rectangle.
 * 
 */
public final class RectangleEdge implements Serializable {

	/** Top. */
	public static final RectangleEdge TOP = new RectangleEdge(
			"RectangleEdge.TOP");

	/** Bottom. */
	public static final RectangleEdge BOTTOM = new RectangleEdge(
			"RectangleEdge.BOTTOM");

	/** Left. */
	public static final RectangleEdge LEFT = new RectangleEdge(
			"RectangleEdge.LEFT");

	/** Right. */
	public static final RectangleEdge RIGHT = new RectangleEdge(
			"RectangleEdge.RIGHT");

	/** The name. */
	private String name;

	/**
	 * Private constructor.
	 * 
	 * @param name
	 *            the name.
	 */
	private RectangleEdge(final String name) {
		this.name = name;
	}

	/**
	 * Returns a string representing the object.
	 * 
	 * @return The string.
	 */
	public String toString() {
		return this.name;
	}

	/**
	 * Returns <code>true</code> if this object is equal to the specified
	 * object, and <code>false</code> otherwise.
	 * 
	 * @param o
	 *            the other object.
	 * 
	 * @return A boolean.
	 */
	public boolean equals(final Object o) {

		if (this == o) {
			return true;
		}
		if (!(o instanceof RectangleEdge)) {
			return false;
		}

		final RectangleEdge order = (RectangleEdge) o;
		if (!this.name.equals(order.name)) {
			return false;
		}

		return true;

	}

	/**
	 * Returns a hash code value for the object.
	 * 
	 * @return the hashcode
	 */
	public int hashCode() {
		return this.name.hashCode();
	}

	/**
	 * Returns <code>true</code> if the edge is <code>TOP</code> or
	 * <code>BOTTOM</code>, and <code>false</code> otherwise.
	 * 
	 * @param edge
	 *            the edge.
	 * 
	 * @return A boolean.
	 */
	public static boolean isTopOrBottom(final RectangleEdge edge) {
		return (edge == RectangleEdge.TOP || edge == RectangleEdge.BOTTOM);
	}

	/**
	 * Returns <code>true</code> if the edge is <code>LEFT</code> or
	 * <code>RIGHT</code>, and <code>false</code> otherwise.
	 * 
	 * @param edge
	 *            the edge.
	 * 
	 * @return A boolean.
	 */
	public static boolean isLeftOrRight(final RectangleEdge edge) {
		return (edge == RectangleEdge.LEFT || edge == RectangleEdge.RIGHT);
	}

	/**
	 * Returns the opposite edge.
	 * 
	 * @param edge
	 *            an edge.
	 * 
	 * @return The opposite edge.
	 */
	public static RectangleEdge opposite(final RectangleEdge edge) {
		RectangleEdge result = null;
		if (edge == RectangleEdge.TOP) {
			result = RectangleEdge.BOTTOM;
		} else if (edge == RectangleEdge.BOTTOM) {
			result = RectangleEdge.TOP;
		} else if (edge == RectangleEdge.LEFT) {
			result = RectangleEdge.RIGHT;
		} else if (edge == RectangleEdge.RIGHT) {
			result = RectangleEdge.LEFT;
		}
		return result;
	}

	/**
	 * Returns the x or y coordinate of the specified edge.
	 * 
	 * @param rectangle
	 *            the rectangle.
	 * @param edge
	 *            the edge.
	 * 
	 * @return The coordinate.
	 */
	public static double coordinate(final Rectangle2D rectangle,
			final RectangleEdge edge) {
		double result = 0.0;
		if (edge == RectangleEdge.TOP) {
			result = rectangle.getMinY();
		} else if (edge == RectangleEdge.BOTTOM) {
			result = rectangle.getMaxY();
		} else if (edge == RectangleEdge.LEFT) {
			result = rectangle.getMinX();
		} else if (edge == RectangleEdge.RIGHT) {
			result = rectangle.getMaxX();
		}
		return result;
	}

	/**
	 * Ensures that serialization returns the unique instances.
	 * 
	 * @return The object.
	 * 
	 * @throws ObjectStreamException
	 *             if there is a problem.
	 */
	private Object readResolve() throws ObjectStreamException {
		RectangleEdge result = null;
		if (this.equals(RectangleEdge.TOP)) {
			result = RectangleEdge.TOP;
		} else if (this.equals(RectangleEdge.BOTTOM)) {
			result = RectangleEdge.BOTTOM;
		} else if (this.equals(RectangleEdge.LEFT)) {
			result = RectangleEdge.LEFT;
		} else if (this.equals(RectangleEdge.RIGHT)) {
			result = RectangleEdge.RIGHT;
		}
		return result;
	}

}
